As a power semiconductor device, for example, there is a vertical power MOSFET (Metal Oxide Semiconductor Field Effect Transistor). In the vertical power MOSFET, there is a constitution in which a sense electrode for detecting a current flowing in the device is formed. Therefore, the breakdown of the device due to an over-current can be prevented.
In the vertical power MOSFET having a sense electrode, the current ratio (sense ratio) of a current flowing in the sense electrode and a current flowing in a source electrode is temperature dependant.